Re: [PATCH v3] kvm: svm: Use the hardware provided GPA instead of page walk

[David Hildenbrand]

> > > +     * If the exit was due to a NPF we may already have a GPA.
> > > +     * If the GPA is present, use it to avoid the GVA to GPA table walk.
> > > +     * Note, this cannot be used on string operations since string
> > > +     * operation using rep will only have the initial GPA from the NPF
> > > +     * occurred.
> > > +     */
> >
> > I was wondering if it would make sense to get rid of gpa_available and
> > rather define a new function:
> >
> > bool exception_gpa_valid(struct kvm_vcpu)
> > {
> >     // check if svm
> >     // check if exit code is NPF
> >     // check ctxt
> > }
>
> No, this would be a layering violation.  The emulator ops don't know
> about svm and exit codes (and in fact it's trivial to implement this
> optimization for vmx, with a slightly different logic), so we need to
> have gpa_available.

I was rather thinking about adding an vmx/svm independent callback, 
which would return false for vmx for now. I just saw the variable
and was wondering if it is really necessary.

--

David